1. Field of the Invention
This invention relates to a swimmer protection and pool safety warning device, and particularly to such a device which will result in a warning signal if a swimmer remains below a predetermined depth for more than a predetermined time.
2. Related Art
It can occur that a swimmer, or other person in a pool, as a result of illness, or some form of accident, will sink down into the water. Such an occurrence may not be noted by other persons, including lifeguards, particularly if there are many people in the pool. A person may be under water for a long time before being noticed and it can be too late to save life.
Various devices exist for detecting persons falling off of boats. Such devices generally rely on some form of water actuated detector to cause an alarm to be sounded. Other systems constantly monitor the positions of persons, such as members of the crew of a boat. If someone moves outside a predetermined envelope, then an alarm sounds.
Such devices are not suitable for use by swimmers who can quite safely remain in the water for a long time, and may frequently leave the water and return. Also such persons may dive and go below a particular depth and then rise back up to the surface. It would be most unsatisfactory for any device to result in numerous alarms due to quite normal activities of a person in a pool.